Downhole bidirectional sealing device

Abstract

The utility model relates to the technical field of sealing devices, in particular to an underground two-way sealing device which comprises a wellhead device body, a polish rod is arranged in the wellhead device body in a penetrating mode, an annular fixing plate is arranged in the wellhead device body, and a two-way sealing assembly is arranged in the wellhead device body and located above the annular fixing plate. The bidirectional sealing assembly comprises a first sealing ring, a second sealing ring, a third sealing ring and a fourth sealing ring which are sequentially arranged from top to bottom, and a sealing cover is arranged at the top end of the wellhead device body. According to the underground bidirectional sealing device, the annular fixing plate plays a role in supporting the bidirectional sealing assembly, the sealing cover fixes the bidirectional sealing assembly in the wellhead device body, and the bottom end of the polished rod sequentially penetrates through the sealing cover and the bidirectional sealing assembly; the inner walls of the first rubber inner ring, the first graphite ring, the second graphite ring and the second rubber inner ring are all tightly attached to the outer wall of the polish rod, and when the polish rod moves up and down, it can be ensured that oil gas in an oil-gas well cannot leak from the well head device body.

Description

Technical Field

[0001] The utility model relates to the technical field of sealing devices, in particular to an underground bidirectional sealing device. Background Art

[0002] In the current oil and gas production operations, preventing underground oil and gas leakage is one of the important tasks. Oil and gas leakage will not only cause the loss of oil and gas resources, but also may cause environmental pollution and production safety accidents. In the process of oil production, the rod of the pumping unit needs to go through the process of upstroke and downstroke. In oil production, it is usually necessary to set a wellhead device at the wellhead to achieve sealing, so as to prevent oil leakage and other phenomena during the oil pumping process, which will cause environmental pollution.

[0003] The patent with the publication number CN215213408U discloses a double-sealed wellhead device for oil and gas production. It includes a wellhead device body, a retaining ring fixed inside the wellhead device body, a sealing ring fixed inside the retaining ring, a light rod passing through the sealing ring and connected with the sealing ring in a sliding and sealing manner, a lower cone sleeve concentric with the retaining ring fixed at the lower end of the retaining ring, an upper cone sleeve fixed inside the wellhead device body above the retaining ring, a conical sealing sleeve installed inside the upper cone sleeve, the outer edge of the light rod and the inner edge of the sealing sleeve are connected in a sliding and sealing manner, the outer edge of the sealing sleeve is in sealing contact with the inner edge of the upper cone sleeve, a pressure ring is provided on the upper sleeve of the light rod above the sealing sleeve, a top ring is fixed at the lower end of the pressure ring, the lower end of the top ring is tightly against the upper end of the sealing sleeve, a cover ring is detachably fixed and sealed at the upper end of the wellhead device body, and a spring is provided on the upper sleeve of the light rod between the cover ring and the pressure ring. The utility model has good sealing performance, has a double sealing effect, can prevent oil and gas from leaking, avoids waste of oil and gas, avoids pollution of the surrounding environment, and has a long service life.

[0004] The above-mentioned prior art polished rod is sealed and connected with the sealing ring and the sealing sleeve, and the sealing ring and the sealing sleeve realize double sealing of the polished rod, but the sealing ring is arranged in the retaining ring, and the lower graphite ring is arranged in the lower cone sleeve. When the sealing ring and the lower graphite ring are worn, the sealing ring and the lower graphite ring cannot be replaced due to the obstruction of the upper cone sleeve, resulting in the need to replace the wellhead device as a whole, which increases the subsequent maintenance cost. In view of this, we propose a downhole bidirectional sealing device. Utility Model Content

[0005] The purpose of the utility model is to provide a downhole bidirectional sealing device to solve the problems raised in the above background technology.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A downhole bidirectional sealing device, comprising a wellhead device body, a polished rod is provided in the wellhead device body, an annular fixing plate is provided in the wellhead device body, a bidirectional sealing assembly is provided in the wellhead device body and above the annular fixing plate, and the bidirectional sealing assembly comprises a first sealing ring, a second sealing ring, a third sealing ring and a fourth sealing ring which are arranged in sequence from top to bottom;

[0008] A first annular groove is formed at the top of the inner wall of the first sealing ring, a first rubber inner ring is formed in the first annular groove, a third annular groove is formed at the top of the inner wall of the second sealing ring, a first graphite ring is formed in the third annular groove, a fourth annular groove is formed at the bottom of the inner wall of the third sealing ring, a second graphite ring is formed in the fourth annular groove, a fifth annular groove is formed at the bottom of the inner wall of the fourth sealing ring, a second rubber inner ring is formed in the fifth annular groove, and a removable sealing cover is formed at the top of the wellhead device body;

[0009] The annular fixing plate supports the bidirectional sealing assembly, the sealing cover fixes the bidirectional sealing assembly in the wellhead device body, and the bottom end of the polished rod passes through the sealing cover and the bidirectional sealing assembly in sequence.

[0010] Preferably, an annular connecting plate is provided on the outer wall at the top of the wellhead device body, and the annular connecting plate and the sealing cover are locked by bolts and nuts, so that the staff can easily disassemble and assemble the sealing cover.

[0011] Preferably, the inner walls of the first rubber inner ring, the first graphite ring, the second graphite ring and the second rubber inner ring are all tightly fitted with the outer wall of the polished rod, and when the polished rod moves up and down, it can ensure that the oil and gas in the oil and gas well cannot leak from the wellhead device body.

[0012] Preferably, a second annular groove is provided at the top of the outer wall of the first sealing ring, a first rubber outer ring is provided in the second annular groove, and the outer wall of the first rubber outer ring is tightly fitted with the inner wall of the wellhead device body to ensure that outside air does not enter the bottom of the oil and gas well from the connection between the first sealing ring and the wellhead device body.

[0013] Preferably, the bottom of the second sealing ring is provided with four pressure rods arranged in a circular array, and the top of the third sealing ring is provided with four circular slots arranged in a circular array, and the bottom ends of the four pressure rods are respectively inserted into the four circular slots, and the relative positions of the second sealing ring and the third sealing ring are fixed by the four pressure rods to prevent the third sealing ring from moving upward with the movement of the light rod when in use.

[0014] Preferably, the top of the third sealing ring is further provided with four circular holes arranged in a circular array, and the four circular holes are respectively arranged alternately with four circular slots to avoid mutual interference between the pressure rod and the connecting rod.

[0015] Preferably, the top of the fourth sealing ring is provided with four connecting rods arranged in an annular array, the four connecting rods pass through four circular holes respectively, and the outer sides of the four connecting rods are sleeved with springs, the top ends of the springs are against the bottom of the second sealing ring, and the bottom ends of the springs are against the top of the third sealing ring. Under the action of the springs, the top of the first sealing ring is tightly fitted with the bottom of the sealing cover, and the bottom of the fourth sealing ring is tightly fitted with the top of the annular fixing plate;

[0016] The top end of the connecting rod abuts against the bottom end of the second sealing ring. When the bidirectional sealing assembly needs to be taken out, the third sealing ring and the fourth sealing ring can be lifted upwards through the connecting rod, thereby facilitating the staff to take out the third sealing ring and the fourth sealing ring.

[0017] Preferably, a sixth annular groove is provided at the bottom of the outer wall of the fourth sealing ring, a second rubber outer ring is provided in the sixth annular groove, and the outer wall of the second rubber outer ring is tightly fitted with the inner wall of the wellhead device body to ensure that the oil and gas below the oil and gas well will not leak from the connection between the fourth sealing ring and the wellhead device body.

[0018] Compared with the prior art, the beneficial effects of the utility model are:

[0019] 1. The downhole bidirectional sealing device, the annular fixing plate supports the bidirectional sealing assembly, the sealing cover fixes the bidirectional sealing assembly in the wellhead device body, the bottom end of the polished rod passes through the sealing cover and the bidirectional sealing assembly in sequence, the inner walls of the first rubber inner ring, the first graphite ring, the second graphite ring and the second rubber inner ring are all tightly fitted with the outer wall of the polished rod, when the polished rod moves up and down, it can ensure that the oil and gas in the oil and gas well cannot leak from the wellhead device body.

[0020] 2. In the downhole two-way sealing device, the outer wall of the first rubber outer ring is tightly fitted with the inner wall of the wellhead device body, ensuring that outside air will not enter the oil and gas well below from the connection between the first sealing ring and the wellhead device body, and the outer wall of the second rubber outer ring is tightly fitted with the inner wall of the wellhead device body, ensuring that the oil and gas below the oil and gas well will not leak from the connection between the fourth sealing ring and the wellhead device body, thereby achieving a two-way sealing effect.

[0021] 3. For the downhole two-way sealing device, when it is necessary to take out the two-way sealing assembly, the staff first disassembles the sealing cover, then takes out the first sealing ring, then takes out the second sealing ring, then pulls the connecting rod upward, lifts the fourth sealing ring upward through the connecting rod, and the third sealing ring moves upward synchronously with the fourth sealing ring, thereby facilitating the staff to take out the two-way sealing assembly, and then facilitating the staff to replace the worn first rubber inner ring, the first graphite ring, the second graphite ring or the second rubber inner ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall first-view structure of the utility model;

[0023] Figure 2 It is a schematic diagram of the overall structure of the utility model from a second viewing angle;

[0024] Figure 3 It is a schematic diagram of the overall cross-sectional structure of the utility model;

[0025] Figure 4 It is a schematic diagram of the structure of the bidirectional sealing component in the utility model;

[0026] Figure 5 It is a schematic diagram of the assembly structure of the first sealing ring, the first rubber inner ring and the first rubber outer ring in the utility model;

[0027] Figure 6 It is a schematic diagram of the assembly structure of the second sealing ring and the first graphite ring in the utility model;

[0028] Figure 7 This is a schematic diagram of the assembly structure of the third sealing ring and the second graphite ring in the utility model;

[0029] Figure 8 It is a partial structural schematic diagram of the bidirectional sealing assembly in the utility model.

[0030] In the figure: 1, wellhead device body; 10, annular fixing plate; 11, annular connecting plate; 2, bare rod; 3, sealing cover; 4, bidirectional sealing assembly; 40, first sealing ring; 400, first annular groove; 401, second annular groove; 41, second sealing ring; 410, pressure rod; 411, third annular groove; 42, third sealing ring; 420, circular slot; 421, circular hole; 422, fourth annular groove; 43, fourth sealing ring; 430, connecting rod; 431, fifth annular groove; 432, sixth annular groove; 44, first rubber inner ring; 45, first rubber outer ring; 46, first graphite ring; 47, second graphite ring; 48, second rubber inner ring; 49, second rubber outer ring; 402, spring. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0033] See also Figure 1-Figure 8 , the utility model provides a technical solution:

[0034] A downhole bidirectional sealing device comprises a wellhead device body 1, a polished rod 2 is provided in the wellhead device body 1, an annular fixing plate 10 is provided in the wellhead device body 1, a bidirectional sealing assembly 4 is provided in the wellhead device body 1 and above the annular fixing plate 10, and the bidirectional sealing assembly 4 comprises a first sealing ring 40, a second sealing ring 41, a third sealing ring 42 and a fourth sealing ring 43 which are arranged in sequence from top to bottom;

[0035] A first annular groove 400 is formed at the top of the inner wall of the first sealing ring 40, and a first rubber inner ring 44 is formed in the first annular groove 400; a third annular groove 411 is formed at the top of the inner wall of the second sealing ring 41, and a first graphite ring 46 is formed in the third annular groove 411; a fourth annular groove 422 is formed at the bottom of the inner wall of the third sealing ring 42, and a second graphite ring 47 is formed in the fourth annular groove 422; a fifth annular groove 431 is formed at the bottom of the inner wall of the fourth sealing ring 43, and a second rubber inner ring 48 is formed in the fifth annular groove 431; a removable sealing cover 3 is formed at the top of the wellhead device body 1;

[0036] The annular fixing plate 10 supports the bidirectional sealing assembly 4 , and the sealing cover 3 fixes the bidirectional sealing assembly 4 in the wellhead device body 1 . The bottom end of the polished rod 2 passes through the sealing cover 3 and the bidirectional sealing assembly 4 in sequence.

[0037] In this embodiment, an annular connecting plate 11 is provided on the outer wall of the top of the wellhead device body 1 , and the annular connecting plate 11 and the sealing cover 3 are locked by bolts and nuts, so that the staff can easily disassemble and assemble the sealing cover 3 .

[0038] Specifically, the inner walls of the first rubber inner ring 44, the first graphite ring 46, the second graphite ring 47 and the second rubber inner ring 48 are tightly fitted with the outer wall of the polished rod 2, so that when the polished rod 2 moves up and down, it can ensure that the oil and gas in the oil and gas well cannot leak from the wellhead device body 1.

[0039] Furthermore, a second annular groove 401 is provided at the top of the outer wall of the first sealing ring 40, and a first rubber outer ring 45 is provided in the second annular groove 401. The outer wall of the first rubber outer ring 45 fits tightly with the inner wall of the wellhead device body 1, ensuring that outside air does not enter the bottom of the oil and gas well from the connection between the first sealing ring 40 and the wellhead device body 1.

[0040] Furthermore, four pressure rods 410 arranged in a circular array are provided at the bottom of the second sealing ring 41, and four circular slots 420 arranged in a circular array are opened at the top of the third sealing ring 42. The bottom ends of the four pressure rods 410 are respectively inserted into the four circular slots 420, and the relative positions of the second sealing ring 41 and the third sealing ring 42 are fixed by the four pressure rods 410 to prevent the third sealing ring 42 from moving upward with the movement of the light rod 2 when in use.

[0041] Furthermore, four circular holes 421 arranged in a circular array are formed on the top of the third sealing ring 42 . The four circular holes 421 are arranged alternately with the four circular slots 420 to avoid mutual interference between the pressure rod 410 and the connecting rod 430 .

[0042] Furthermore, four connecting rods 430 arranged in an annular array are provided on the top of the fourth sealing ring 43, and the four connecting rods 430 pass through the four circular holes 421 respectively. The outer sides of the four connecting rods 430 are sleeved with springs 402, and the top of the spring 402 abuts against the bottom of the second sealing ring 41, and the bottom of the spring 402 abuts against the top of the third sealing ring 42. Under the action of the spring 402, the top of the first sealing ring 40 is tightly fitted with the bottom of the sealing cover 3, and the bottom of the fourth sealing ring 43 is tightly fitted with the top of the annular fixing plate 10;

[0043] The top of the connecting rod 430 abuts against the bottom of the second sealing ring 41. When the bidirectional sealing assembly 4 needs to be removed, the third sealing ring 42 and the fourth sealing ring 43 can be lifted upward through the connecting rod 430, thereby facilitating the staff to remove the third sealing ring 42 and the fourth sealing ring 43.

[0044] Furthermore, a sixth annular groove 432 is provided at the bottom of the outer wall of the fourth sealing ring 43, and a second rubber outer ring 49 is provided in the sixth annular groove 432. The outer wall of the second rubber outer ring 49 fits tightly with the inner wall of the wellhead device body 1, ensuring that the oil and gas below the oil and gas well will not leak from the connection between the fourth sealing ring 43 and the wellhead device body 1.

[0045] When the downhole bidirectional sealing device of this embodiment is in use, when the polished rod 2 moves up and down, since the inner walls of the first rubber inner ring 44, the first graphite ring 46, the second graphite ring 47 and the second rubber inner ring 48 are tightly fitted with the outer wall of the polished rod 2, it can be ensured that the oil and gas in the oil and gas well cannot leak from the connection between the polished rod 2 and the bidirectional sealing assembly 4, the outer wall of the first rubber outer ring 45 is tightly fitted with the inner wall of the wellhead device body 1, ensuring that the outside air will not enter the oil and gas well from the connection between the first sealing ring 40 and the wellhead device body 1, and the outer wall of the second rubber outer ring 49 is tightly fitted with the inner wall of the wellhead device body 1, ensuring that the oil and gas in the oil and gas well cannot leak from the connection between the first sealing ring 40 and the wellhead device body 1. The oil and gas will not leak from the connection between the fourth sealing ring 43 and the wellhead device body 1, thereby achieving the effect of two-way sealing; when it is necessary to remove the two-way sealing assembly 4, the staff first disassembles the sealing cover 3, then removes the first sealing ring 40, and then removes the second sealing ring 41, and then pulls the connecting rod 430 upward, and lifts the fourth sealing ring 43 upward through the connecting rod 430, and the third sealing ring 42 moves up synchronously with the fourth sealing ring 43, so that it is convenient for the staff to take out the two-way sealing assembly 4, and then it is convenient for the staff to replace the worn first rubber inner ring 44, the first graphite ring 46, the second graphite ring 47 and the second rubber inner ring 48.

[0046] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the utility model and are not used to limit the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A downhole bidirectional sealing device, comprising a wellhead device body (1), wherein a polished rod (2) is provided through the wellhead device body (1), and characterized in that: An annular fixing plate (10) is provided in the wellhead device body (1), and a bidirectional sealing assembly (4) is provided in the wellhead device body (1) and above the annular fixing plate (10). The bidirectional sealing assembly (4) comprises a first sealing ring (40), a second sealing ring (41), a third sealing ring (42) and a fourth sealing ring (43) which are arranged in sequence from top to bottom. A first annular groove (400) is provided at the top of the inner wall of the first sealing ring (40), and a first rubber inner ring (44) is provided in the first annular groove (400). The second sealing ring (41) is provided with a first rubber inner ring (44). A third annular groove (411) is formed at the top of the inner wall of the wellhead device (41), a first graphite ring (46) is arranged in the third annular groove (411), a fourth annular groove (422) is formed at the bottom of the inner wall of the third sealing ring (42), a second graphite ring (47) is arranged in the fourth annular groove (422), a fifth annular groove (431) is formed at the bottom of the inner wall of the fourth sealing ring (43), a second rubber inner ring (48) is arranged in the fifth annular groove (431), and a removable sealing cover (3) is provided at the top of the wellhead device body (1).

2. The downhole bidirectional sealing device according to claim 1, characterized in that: An outer wall at the top of the wellhead device body (1) is provided with an annular connecting plate (11), and the annular connecting plate (11) and the sealing cover (3) are locked by bolts and nuts.

3. The downhole bidirectional sealing device according to claim 1, characterized in that: The inner walls of the first rubber inner ring (44), the first graphite ring (46), the second graphite ring (47) and the second rubber inner ring (48) are all tightly fitted to the outer wall of the polished rod (2).

4. The downhole bidirectional sealing device according to claim 1, characterized in that: A second annular groove (401) is provided at the top of the outer wall of the first sealing ring (40), a first rubber outer ring (45) is provided in the second annular groove (401), and the outer wall of the first rubber outer ring (45) is tightly fitted to the inner wall of the wellhead device body (1).

5. The downhole bidirectional sealing device according to claim 1, characterized in that: The bottom of the second sealing ring (41) is provided with four pressure rods (410) arranged in a circular array, the top of the third sealing ring (42) is provided with four circular slots (420) arranged in a circular array, and the bottom ends of the four pressure rods (410) are respectively inserted into the four circular slots (420).

6. The downhole bidirectional sealing device according to claim 5, characterized in that: The top of the third sealing ring (42) is also provided with four circular holes (421) arranged in a circular array, and the four circular holes (421) are respectively arranged alternately with the four circular slots (420).

7. The downhole bidirectional sealing device according to claim 6, characterized in that: Four connecting rods (430) arranged in a circular array are provided on the top of the fourth sealing ring (43), the four connecting rods (430) respectively pass through four circular holes (421), and springs (402) are sleeved on the outside of the four connecting rods (430), the top end of the spring (402) abuts against the bottom of the second sealing ring (41), the bottom end of the spring (402) abuts against the top of the third sealing ring (42), and the top end of the connecting rod (430) abuts against the bottom of the second sealing ring (41).

8. The downhole bidirectional sealing device according to claim 1, characterized in that: A sixth annular groove (432) is provided at the bottom of the outer wall of the fourth sealing ring (43), a second rubber outer ring (49) is provided in the sixth annular groove (432), and the outer wall of the second rubber outer ring (49) is tightly fitted to the inner wall of the wellhead device body (1).

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